Control apparatus for electric-discharge devices



0. E. BUCKLEY v CONTROL APPARATUS FOR ELECTRIC DISCHARGE DEVICES Original Filed Dec. 15. 1917 F/q]. I

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atented Nov. 15, 1927.

UNITED STATES 1,649,016 PATENT oFFIcE.

OLIVER ELLSWORTH BUCKLEY, OF MAPLEWOOD, NEW JERSEY, ASSIGNOR- '10 WES '1'- ERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

CONTROL APPARATUS FOR ELECTRIC-DISCHARGE DEVICES.

Application filed. December 15, 1917, Serial No. 207,329. Renewed April 9, 1927.

Ill heated filament which serves as the source of the electrons. As described in my Patent No. 1,372,798, dated March -29, 1921, such a tube may be used as a vacuum gauge, the

ionization of the gas as detected by a collec-- tor electrode being a measure of the gas pressure. It has been discovered that fluctuations in the gas pressure 'within the vacuum tube give-s corresponding fluctuations in the intensity of the electron discharge from the heated filament. For some gases as oxygen for example, the thermionic activity of the filament varies inversely with changes in the pressure; for other gases, such as hydrogen, the thermionic activity varies directly with the pressure. These fluctuations in the intensity of the electron discharge from the heated filament are objectionable, and in the ease of the vacuum gauge lead to inaccurate results in measuring the gas pressure.

An object of the present invention is to prevent variation such as variations in pressure from producing fluctuations in the intensity of the electron discharge from the heated filament and to insure that the intensity of discharge shall be constant at all gas Kill pressures. This is accomplished by havingthe electron or space current in the vessel directly or indirectly operate a translating device, which in turn controls in a suitable manner the amount of current supplied to the filament.

This invention will be better understood by reference to the following detailed descripticn taken in connection with the accompanying drawings, in which Fig. 1 shows, in connection with a vessel to be evacuated, an ionization manometer, the action of which is regulated in accordance with gins invention. Fig. 2 is a modificaton of Referring to Fig. 1, 4; represents a vessel, the gas pressure of whichis tobe measured.

A connecting tube 5 extends from this vessel to a vessel 6 in which there is enclosed a source of electrons 8 and an electrode 9 serving as an anode. This source of electrons may be of any suitable form, such, for example, as a filament heated by a source of voltage 11. Connected between the elements ,8 and 9 is a source of voltage 12, the positive pole of which is connected to the anode 9. Under these circumstances electron cur negative terminal connected to the member 13 in order that it may be maintained at a potential lower than that of the electron I and the voltage of the source 12 is sufiieiently high, the electrons will acquire sufficient velocity to ionize some of the gasmolecules and there will then be present both negative and positive ions. The posltlve ions will travel to negatively charged electrodes and chiefly to that one which is at the lowestpotential, that is, to the electrode 13. The collection of positive charges on the electrode will give rise to a current from this member 13 through the source of voltage 14, and the presence of this current may be detected by the insertion of any suitable galvanometer 17. Since, for a given setting of the system, "the amount of this current will be proportional to the pressure,.the deflection of the instrument 17 will be an indlcation of the degree of evacuation present in the vessel. 1

In the calibration of such a device it has been found convenient to calibrate for a constant space current in the manometer. It is therefore desirable Whenmeasuring pressure by means of this gauge, that the space curthe space current at a desired value. In the form shown in Fig. 1 this is accomplished by having the current from the source of voltage 12 pass through a relay 19 which controls the short circuit between points 20 and 21 containing the resistance 22. This resistance is also in series with the source of voltage 11 which supplies the heating current for the filament 8. The armature 25 of the relay is normally in contact with the point 26, so that the resistance 22 is short circuited by the lead wires 28 and 29. When the current flowing through the relay 19 is suflicient to cause its armature to be attract- "ed,'the short circuit around the resistance 22 is broken and the heating current instead of passing through the lead wires 28 and 29 is compelled to pass through the'resistance 22, thereby decreasing the current an amount depending upon the value of the resistance. By such an arrangement the space current may be kept between an upper and a lower limiting value, the upper limiting value being obtained when the resistance 22 is short circuited and the lower limiting value being obtained when the short circuit is broken. This resistance should be of such a value that on its insertion the heating current for the filament 8 will be so low that the space current in the vessel 6, which current may for convenience be called the manometer current, will never be greater than the desired amount, whatever the pressure of the gas in the vessel, and when short circuited the heatlng current for the filament will be so large as to furnish at least the desired anode current. It follows, therefore, that whenever the manometer current exceeds the upper hmitlng value desired, that the action of the relay will be such as to attract its armature and insert the resistance 22, consequently reducing the filament temperature and the current flow. As soon as the current is decreased beyond the desired lower limiting value of the current, the relay will release lts armature so that the resistance will be shunted and the filament reheated to the desired temperature. The result of such a process when the pressure in the vessel is undergoing considerable variation will be an intermittent closing and opening of the relay contact, such as to maintain the average value of the current at the value, desired.

A modification of Fig. 1 is shown in Fig. 2, where the manometer current between the filament 8 and the anode 9, instead of actuatlng a relay, is caused to pass through a resistance 35 which is so connected in the input circuit of an audion 37 that the drop of potential across its terminals, due to this current, makes the input electrode 38 of the audion negative with respect to the filament 39. Since, as is well-knownin the art, the intensity of the current between the filament 39 and the anode 40, due to the source of voltage 41, is controlled by the potential of the input electrode 38, it follows, that with the arrangement above described the space current of the audion 37, which we may call the audion current, will be dependent 1n intensity upon the value of the manometer current. In the output circuit of the audion is a relay 43 which on being actuated causes its armature 44 to make contact with the point 45, thereby short circuiting the resistance 22, which is related to the device 6 as in Fig. 1. It is preferable that the adjustable contact 48, for the connection of the grid 38 to the resistance 35, should be so adjusted that when the desired amount of manometer current is flowing, the potential difference produced thereby between the grid 38 and the filament 39 of the audion, is sulficient to reduce the audion current to a value insuflicient to operate the relay 43. With such an adjustment, when the manometer current decreases below the limiting value desired, this decrease will make the grid 38 more positive with respect to the filament 39, thereby sufficiently increasing the audion current to energize the relay 43 and close the contact 45. The lead wires 28 and 29 will then short circuit the resistance 22 so that the manometer current will be increased in the manner described under Fig. 1. An increase beyond the desired value of the manometer current will similarly make the grid 38 more negative with respect to the filament 39 and will reduce the audion current to such a value that the relay releases its armature, thereby breaking the short circuit around resistance 22, which as described above will cause the manometer current to be decreased.

By suitable adjustment of the various parts of such a system and with the proper selection of the upper and lower limiting values of the manometer current, the average value of this current may be made to closely approximate the value desired for each degree of evacuation in the vessel 6.

It is obvious that various modifications may be made in .the structure of the system above described without departing anywise from the spirit of the invention as set forth in the appended claims.

What Is claimed is: e

1. The method of operating a vacuum tube in which the degree of evacuation fluctuates and which contains an electron stream, which method comprises increasing the intensity of said stream with decrease of pressure.

2. The combination of a vacuum tube subjected to different degrees of evacuation,

means for producing an electron stream in said tube and means responsive to a change in the degree of the evacuation of said tube for regulating the intensity of said vstream while permitting the degree of evacuation of said tube to remain substantially constant during the regulation of said stream.

3. The combination of a vessel containing a plurality of electrodes; means for causing one of said electrodes to emit electrons and means for regulating the emission of elec trons from said electrode when variation occurs in the pressure in said vessel while still permitting the degree of evacuation of said vessel to remain substantially. constant during the regulation of said emission.

4. A vessel containing a 'lurality of electrodes, means for establishinga space current between two of said electrodes, means for regulating the intensity of said space current to make said current practically independent, over the desired range, of changes of pressure in said vessel.

5. A vessel containing a plurality of electrodes, means for causing one of said electrodes to emit electrons, means for controlling the rate of emission of electrons from said source in accordance with the pressure within said vessel, said second means comprising a translating device whose operation is dependent upon the rate of electron emission, and means controlled by said translating device for regulating saidfirstmentioned means.

6. A. vessel containing a plurality of electrodes, means for causing one of. said electrodes to emit electrons, means for establishing a space current between said emitting electrode and a second electrode, a translating devicerfassociated with said vessel, the operation of said device being dependent upon the intensity of said space current, and means controlled by said device. for regulating said first-mentioned means whereby said space current is made practically independent of the degreeof eyacuation of said vessel.

7. A vessel containing a plurality of electrodes, a source of current for heating one of said electrodes whereby it is madea source of electrons, an impedance associated with said electrode and said source, means for varying the-amount of said impedance whereby the electron emission from said electrode is made practically independent of changes of the pressure in said vessel.

8. A vessel containing a plurality of electrodes, a source of current for heating one of said electrodes/whereby said electrode is made'a source of electrons, a resistance in series with said electrode and said e l f fintsource, means for varying the amount ol' said resistance whereby the electron emission from said electrode is madelpra'etically independent. of changes in;-tl1e pressure in said vessel.

9. The combination of a vessel subjected to different degreesof evacuation, means for supplying said vessel with an electron stream, a relay responsive to the degrceot evacuation of said vessel, and means controlled by said relay for increasing the intensity of said stream with decrease in prcssure.,

ill. The combination of a vessel subjected to different degrees of evacuation, a vacuum tube of substantially constant pressure associated-therewith, means for removing gas from said vessel and means for controlling I said vacuum tube in response to the degree of evacuation of said vessel.

11. Avessel containing an anode and a cathode, means for establishing a space current between said anode and cathode, an

evacuatediessel, means for establishing a space-current in said evacuated vessel, means whereby the current in said evacuated vessel is controlled by the space current in said first vessel a relay whose operation is controlled by-t 'e space current of said evacuated ,vessel, andmeans controlled by said relay wherebythe space cugrent insaid first vessel is made practically independent of the pressure in said first vessel.

12. A vessel containing an anode and a cathode, means" for heating sald cathode,

means for establishing a space current in said vessel, an'audlon, means for establ shing a space current in said audion, means whereby the space current in said audion is controlled by the space current in said vessel, a

relay whose operation is controlled'by the space current of said audiomand a variableimpedance path associated with said cathode and said heating means said relay.

13. A vessel containing an anode anda inc and controlled by 1 cathode, means for heating said cathode, means for establishing .a space current in 1 said vessel, anqaudion, means for establishing a space current in said audion,'nieans' whereby the space current in said audionis controlledby the space current in said vessel, a relay whose operation is controlled'by the space current of said audion, a variable impedance path in series with said cathode and said heating means and controlled between an upper and a lower limiting value by said relay, whereby the space current in said vessel is made practically the pressure in said vessel.v

14. A. vessel containing a lurality or elec- Ill) independent of trodes and subjected to di erent degrees of evacuation, means for supplying heating current to one of said electrodes, and means res onsive to changes in the evacuation of sai vessel for varylng the value of said current.

. 15. A vessel containing a plurality of electrodes and subjected to difierent degrees of evacuation, means for supplying heating current to one of said electrodes, and means responsive to changes in the evacuation of said vessel for varying the value of said current, said responsive means comprising a relay and a resistance controlled thereby.

16. The combination of a vessel subjected to a wide range of pressure, a vacuum tube associated therewith, means for supplying said tube with an electron stream, means for controlling said stream in response to changes of the pressure in said vessel, and means for subjecting said vessel to a wide range of pressure during the operation of said controlling means.

17. A vacuum tube manometer subjected to varying degrees of evacuation to be measured and comprising cathode and anode electrodes, and a collector electrode for receiving the positive electric charges produced by the ionization of the gas in'said tube, said collector electrode being located on that side of one of said electrodes remote from the other of said electrodes.

18. A vacuum tube manometer subject to varying degrees of evacuation to be measured and comprising cathode and anode electrodes, and a collector electrode for receiving the positive electric charges roduced by the ionization of the gas in said tube, said collector electrode being located on that side of said anode remote from said cathode. V

19. In combination, a vacuum tube having an anode and a cathode, a source of voltage for supplying space current between said anode and cathode, connections for supplying heating current to said cathode, and means for maintaining said space current substantially constant comprising a solenoid controlled when said space current tends to vary for varying the eflective'heating current supplied to said cathode.

20. In combination, an electric discharge device comprising an anode and a cathode provided with external terminals for enabling the heatin of said cathode, a source of-space current or said device, and means responsive to space current changes to control the heating current supplied for reducing said chan es to a low value.

21. In com ination, an electric discharge device comprising an anode and a'cathode, a source of space current for said tube, and means responsive to small changes in said space current for holding said space current substantially constant through the intermediary of variations produced in the temperature of said cathode.

22.In combination, a vacuum tube having an anode and a cathode, a source of space current for said tube, an electric circuit comprising said source and the space current path between said anode and cathode, and means responsive to variations in a characteristic of said circuit for causing said space current to be held substantially constant when the effective im edance between said anode and cathode tends to vary.

23. The combination with an anode and a cathode the degree of pressure between which is subject to variations, of an auxiliary discharge path comprising an anode and a cathode and controlled by variations in said pressure, a solenoid responsive to variations in a characteristic of said ath, and heating circiit connections contro led by said soleno1 24. The combination of cooperating electrodes the degree of evacuation between which is subject to variations, of an auxiliary electric discharge path comprising an anode and a cathode, an auxiliary electrode associated with said anode and cathode and having its potential'responsive to variations in the pressure between said cooperating electrodes, heating circuit connections for one of said cooperating electrodes, and means res onsiveto variations in the potential of sai auxiliary electrode for varying said heating circuit connections.

In lwitness whereof, I hereunto subscribe my name this th day of November A. D.,

OLIVER ELLSWORTH BUCKUFX. [1.8.] 

